Silver, Ag, is a metallic element that has been valued for its use in currency, jewelry, photoprocessing, electronics, and in the medical field. In the past decade, there have been many advances in the field of nanotechnology, including the use of silver and other metal nanoparticles. Silver nanoparticles are currently one of the most common metal nanoparticles found in consumer products. Because of the strong bactericidal properties of Ag(I) and Ag nanoparticles, their unpredictable fate of silver in soil-water environments has become a serious concern. Regulatory agencies now face difficulties revising/developing proper risk assessment methods to protect agroecosystems and human health. This chapter focuses on historical data of Ag interactions in soil environments, including geochemical occurrence, sorption/desorption processes, and mineral dissolution. Where research is sparse, a review of soft and borderline metal (e.g., Cd(II), Hg(II), Tl(I), Cu(II), Zn(II), Pb(II)) soil interactions is included, as analogs to Ag(I) reactivity. In addition, newer data focusing on emerging Ag nanoparticle technology and its activity in soil environments are included.